This invention relates to a self-closing tilting valve sealingly insertable in a lid for a container fillable with product under excess pressure and provided with a valve mounting, which valve comprises
an essentially rigid mandrel member having a base part and a tip part,
an enveloping nozzle member surrounding said mandrel member and having an axial product passage surrounded by an inner wall and receiving said mandrel member therein, a head part with an outlet opening for said axial passageway, a foot part having a bottom opening for said axial passageway, and an intermediate portion extending axially between said head part and said foot part,
the top part of said mandrel member bearing a conically tapered sidewall of axially outwardly increasing diameter, and the head part of said enveloping member having an outer end wall about said outlet opening which outer end wall is correspondingly tapered to sealingly contact said top part sidewall in closed position.
A valve of this kind has been described in U.S. Pat. No. 2,831,620 to T. F. Schlicksupp. However, this kind of valve is not suitable for use with pressurized product-filled containers, in particular, when the internal excess pressure in the container reaches the usual values of, for instance, 3 to 5 bar. Such excess pressures would cause an expansion and/or lateral displacement of the bellow-type central zone provided in the enveloping member of Schlicksupp's valve and thus cause it to open unintentionally.
Valves of the Schlicksupp-type are, therefore, only used for liquids such as toilet water, skin lotions, perfumes and also for creams which are present in the container under no or much less excess pressure.
Another tilting valve of somewhat similar construction has been described in U.S. Pat. No. 3,920,165 to Robert S. Schultz. This valve would indeed be suitable for containers having contents under higher internal pressure. However, in this valve which contains, beside a mandrel member, an internal enveloping member and an external cap member, the tip part of the mandrel member does not remain in contact with the inner wall of the head part of the cap member when the valve is opened. Rather, a spacing apart occurs between both parts, while in the case of the tilting valve according to the invention as well as in the case of Schlicksupp's valve, these two parts should remain in contact with one another in the closed as well as in the opened position. A spacing apart between the two tiltably supported members of the Schultz valve jeopardizes a resealing of the valve after each opening stage, even when the dimensioning of the cap member and the internal enveloping member with respect to each other is very exact, because of the variable support means of the two members. For, the cap member must find support simultaneously on the container lid wall and against a shoulder provided in the sidewall of the enveloping member, which latter must in turn provide support for the mandrel member.
Other valves of the general kind having at least some features similar to those of the initially defined self-closing tilting valve are described in the British Pat. No. 928,841 to Michel, and the U.S. Pat. Nos. 3,406,944 to Barker, 3,759,427 to Stanley et al, and 4,008,834 to Towns.
Differences of structure and function which distinguish these known valves from the self-closing tilting valve of the instant invention will be discussed in detail further below.